Regulating the Oxygen Affinity of Single Atom Catalysts by Dual-atom Design for Enhanced Oxygen Reduction Reaction Activity |
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| Authors: | ZHENG Meng WANG Jin |
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| Affiliation: | 1. College of Materials Science and Engineering, Shenzhen University, Shenzhen 518071, P. R. China;2. College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China |
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| Abstract: | This work chooses Cu/Fe single-atom catalysts(SACs) with weak/strong oxygen affinity to clarify the effect of dual-atom configuration on oxygen reduction reaction(ORR) performance based on density functional theory(DFT) calculations. The stability and ORR activity of single or dual Cu/Fe atomic sites anchored on nitrogen-doped graphene sheets(Cu-N4-C, Cu2-N6-C, Fe-N4-C, and Fe2-N6-C) are investigated, and the results indicate the dual-atom catalysts(Cu2-N6-C and Fe2-N6-C) are thermodynamically stable enough to avoid sintering and aggregation. Compared with single-atom active sites of Cu-N4-C, which show weak oxygen affinity and poor ORR performance with a limiting potential of 0.58 V, the dual-Cu active sites of Cu2-N6-C exhibit enhanced ORR activity with a limiting potential up to 0.87 V due to strengthened oxygen affinity. Interestingly, for Fe SACs with strong oxygen affinity, the DFT results show that the dual-Fe sites stabilize the two OH* ligands structure[Fe2(OH)2-N6-C], which act as the active sites during ORR process, resulting in greatly improved ORR performance with a limiting potential of 0.90 V. This study suggests that the dual-atom design is a potential strategy to improve the ORR performance of SACs, in which the activity of the single atom active sites is limited with weak or strong oxygen affinity. |
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| Keywords: | Single-atom catalyst Dual-atom Oxygen reduction reaction(ORR) Oxygen affinity Density functional theory(DFT) |
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